I'm seeing a lot of Modern Warfare (the first one) mods out there, and I've come across at least one post that says that Activision released official modding tools for CoD4, but I can't seem to find them, or any reference to them on official websites.

Have official tools been released? Or are all these modding tools the result of reverse engineering and clever hacking, ala Diablo 2? I'm interested in getting into modding myself, I used to do Duke3D maps with the Build engine back in the day, even had a book on it, and it'd be great if I could do